Railway signaling system with automatic meets between trains



Dec. 8, 1959 1- P. MARPLE. 2,916,612

RAILWAY SIGNALING SYSTEM WITH AUTOMATIC MEETS BETWEEN TRAINS Filed Dec.24, 1956 9 Sheets-Sheet 1 FIG. I.

OFFICE CONTROL IN V EN TOR.

TRMARPLE HIS ATTORNEY FlG.5B.

Dec. 8, 1959 1'. P. MARPLE 2,915,612

RAILWAY SIGNALING SYSTEM wmx AUTOMATIC MEETS BETWEEN TRAINS Filed Dec.24. 1956 e Sheets-Sheet 2 u Gw Q 0 do Q a 0 0 6 0 2 z 0 :.m m zm L NEH C0 T0 HIS ATTORNEY Dec. 8, 1959 "r. P. MARPLE 2,916,612

RAILWAY SIGNALING SYSTEM WITH AUTOMATIC MEETS BETWEEN TRAINS Filed Dec.24, 1956 9 Sheets-Sheet 4 22401 H): INVENTOR.

4T.P.MARPLE HIS ATTORNEY Dec. 8, 1959 T. P. MARPLE 2,916,612

RAILWAY SIGNALING SYSTEM WITH AUTOMATIC MEETS BETWEEN TRAINS Filed D90.24, 1956 9 s s 7 "'1'? 53 FIG.3E. nos s-L. I 2 0 I I I I I I r-fi l r 1l -r- I 3 5a I I 4 T'I I I I L'* l m I I I I l .v. I PUSH BUTTON I +-Ie=I, D I AND :.L. CODE RELAY I I I I v NETWORK I I I I I I SIMILAR I l II I I TO THAT I I- (NX) I splgwgAm I m I E4TK I I 45s I148 I I I I I I92M I l I I94 m I I |95I I I l I I79: I I we I I H) I In I 4m n72 H I I II28 (I) l I Mm I I- I 250 249 l I 4ATN I 232 23| H 4ANE I H.) INVENTOR.

T.P.MARPLE HIS ATTORNEY Dec. 8, 1959 'r. P. MARPLE 2,916,612

RAILWAY SIGNALING SYSTEM WITH AUTOMATIC MEETS BETWEEN TRAINS Filed Dec.24, 1956 9 Sheets-Sheet 8 FIG. 3F.

7RWK 9RWK EL (BX) I I I |98 I 93 I 2 L0 I I03 I F4 1 l 5 f r-O I l IF-GD k I I I5 1 I -u i V I I 6 D i I LR v i l I INVENTOR. T. PQMARPLE'HIS ATTORNEY kwww 2,916,612 RAILWAY srcmguuc SYSTEM WITH uwoumc MEETSBETWEEN mms Filed m. 24, 1956 T. P. MARPLE 9 Sheets-Sheet 9 INVENTOR.

PIrILIIIIIIIIIII IQ mJP m mm iukm rw 29.29232200 M000 T. P.MARPLE HISATTORNEY Unit dfirm Pam RAILWAY SIGNALING SYSTEM WITH AUTO- MATIC MEETSBETWEEN TRAINS Thomas P. Marple, Rochester, N.Y., assignor to GeneralRailway Signal Company, Rochester, N.Y.

ApplicationDecemher 24, 1956, Serial No. 630,273

Claims. (Cl. 246-2) This invention relates to railway signaling systems;and more particularly pertains to signaling systems for stretches ofsingle track which are provided with spaced passing sidings to permittrain movements in both directions.

In systems of the so-called centralized trafiic control type extensivestretches of trackway may be placed under the jurisdiction of a centralcontrol office. A dispatcher, or operator, is provided with a controlpanel having a miniature track diagram representing the stretch of trackunder his supervision. Control levers are provided on such panel forcontrolling track switches and signals at various field locations; and,indication lights are also provided on the panel to indicate particularconditions such as the conditions of track switches, signals anddetector track circuits.

In most systems, the control ofiice is connected to the various switchand signal locations by a code type com-' munication system which, whenactivated, transmits selected control and indication codes between thecontrol office and field locations. Such systems require the operator toarrange meets between opposing trains atrpassing siding locations bymanipulating track switch and signal control levers in accordance withthe desired routing arrangement. The code communication apparatus isthen activated to transmit selected control codes to the siding endlocations.

The arrangement of meets between trains is usually based on a trainclassification basis under which some trains are superior to others.Thus, for example, a freight train may be routed into a siding to awaitthe passing of a fast passenger train which may be moving in either thesame or oposite direction. When the trains are past the point ofpossible conflict the operator causes the transmission of selectedcontrols to the siding end locations for operating track switches andsignals to allow the trains :to depart from the passing siding location.

At all times the dispatcher, or operator, is aware of train positions byobserving track occupancy lights in the track diagram. However, theoperator must be able to mentally correlate occupancy indications withparticular trains.

In view of the above considerations, the present invention. proposes theuse of storage means, or train describers, which can be operated tostore descriptions of train classifications for trains approachingsiding end locations; and, such descriptions are used to arrange routesfor trains and to arrange meets between trains automatically. Throughthe use of a plurality of storage means and interconnecting transfercircuits a train description can be advanced as the train advancesthrough successive trackcircuited sections. Thus, a descriptionintroduced into a storage unit as a train enters a block can be advancedby the train to a storage unit at a siding end location, and can be usedto initiate controls for routing the train through either the main trackor the passing siding.

Since storage means are provided at both ends of a siding, a comparisonbetween concurrently stored descriptions for opposing trains is made,and the superior description determines which train will be routed intothe siding.

In the case of identical classes of opposing trains identified byconcurrently stored descriptions, the present invention provides meansfor arbitrarily giving superiority to one train on a directional basis.

control manipulations, thereby simplifying operating pro cedures.

Once a meet between trains is effected and both trains are clear of thedetector track circuits associated with the track switches at the sidingend locations, the switches I and signals must be controlled to permitthe trains to proceed. This can be done either by controls initiated bythe dispatcher or automatically. The present invention, therefore,provides both manual and automatic control means for arranging leavingmoves by trains.

As previously noted, most systems require the dispatcher to be able tomentally correlate track occupancy indications with particular trains.The use of suitable multiple position indicators which can displayactual train identification numbers as well as store such numbers incontact positions can greatly aid the dispatcher in keeping abreast ofchanging traflic conditions. One type of indicator which can be employedfor embodying the present invention is of the type disclosed in theco-pending U.S. application Serial No. 580,123 of G. E. Marsh filedApril 23, 1956. Such indicator is operable to any one of a plurality ofpositions in which particular electrical circuits are opened and closedby its contacts, and the propercharacter for that position is located ona tape Thus, such an indicator can. be used as a code storage means andalso beoperable to behind a display opening.

visually describe a train. The present disclosure provides means foroperating such indicators and for transferring descriptions betweenindicators so that train movements can be traced visually.

Another object of this invention is to provide control circuitsresponsive to stored train descriptions for automatically routing trainsand arranging meets between trains at passing siding locations.

Another object of this invention is to provide means for automaticallyarranging meets between trains of the same classification or degree ofsuperiority.

A further object of this invention is to provide a con- 7 trol systememploying multi-position indicators for displaying train identificationcharacters and for storing train classification descriptions.

Other objects, purposes and characteristic features of the presentinvention will be in part pointed out as the description progresses, andwill be in part obvious from the accompanying drawings, in which:

Fig. 1 shows diagrammatically a stretch of railway track and a passingsiding, along with a control oifice,

wayside locations and signaling apparatus;

Fig. 2 shows diagrammatically a portion of a control panel having aminiature track diagram representing the stretch of track in Fig. l, andhaving various control and indication devices;

Figs. 3A-3E when placed together show diagrammati- Patented Dec. 8, 1959V,

In addition, the present invention provides means for decoding traindescriptions cally control oflice circuits for controlling andindicating train movements through the stretch of track in Fig. 1;

Fig. 4 is an arrangement plan showing how Figs. 3A 3F must. be arrangedto present a complete circuit diagram.

Figs. 5A and 5B when placed together form. a code chart showing thecorrelation between the operating positions of a multi-positionindicator and arbitrary train classification descriptions; and

Fig. 6 shows diagrammatically circuit means for controlling codecommunication apparatus by the circuits shown in Figs. 3A-3F.

For the purpose of simplifying the illustration and facilitating in theexplanation, the various parts and circuits constituting the embodimentof the invention have been shown diagrammatically and certainconventional illustrations have been employed, the drawings having beenmade more with the purpose of making it easy to understand theprinciples and mode of operation, than with the idea of illustrating thespecific construction and arrangement of parts that would be employed inpractice. Thusgthe various relays and their contacts are illustrated ina conventional manner, and symbols are used to indicate connections tothe terminals of batteries, or other sources of electric current,instead of showing all of the Wiring connections to these terminals.

The symbols and are employed to indicate the positive and negativeterminals, respectively, of suitable batteries, or other sources ofdirect current; and the circuits with which these symbols are usedalways have current flowing in the same direction. The symbols (BX) and(NX) represent connections to the opposite terminals of an alternator,transformer, or other source of alternating current energy.

The organization and utility of the present invention will be disclosedthrough a description of one form of circuit organization which can beapplied to control and indicate traffic and signaling conditions in atypical portion of a railway (see Fig. 1).

Fig. 1 represents a stretch of track and an associated passing siding.It is assumed that the trackway shown isa portion of an extensivestretch of single track along which passing sidings are provided atspaced intervals. The stretch of track and passing siding are dividedinto track sections, such as lAT, 1T, 2T, 3T, 4T and 4AT, which haveassociated track circuits for detecting trains. Using commonterminology, track sections IAT and 4AT are approach track sections,while track sections 2T and ST are referred to, respectively, as themain and siding track sections. The passing siding is connected at itsends to the stretch of track by power operable track switches 7W and 9Wwhich are selectively positioned by switch machines 75M and 9SM. Eachtrack switch is protected by a detector track circuit associated with ashort detector track section, such as sections 7DT and 9DT. The varioustrack sections are electrically insulated from each other by insulatedrail joints 10.

Train movements through the stretch of track and passing siding aregoverned by signals. Signal 6R governs trains moving to the right fromtrack section 1T into either track section 2T or 3T, while signal 8Lgoverns trains moving to the left from track section 4T into. eithertrack section 2T or 3T. Trains leaving either track section 2T or 3T aregoverned by signals 6LA or 6LB if moving to the left, and by signals 8RAor SRB if moving to the right. Approach signals, such as signals 11, arelocated in advance of each siding end to govern approaching trains.Intermediate signals 12 are shown in accordance with usual practice.

The switch machines and signals can be of any of a number of well-knownelectroresponsive types.

It'is assumed that the siding end locations areunder the-jurisdiction ofa central control ofiice whichmay belocated at a considerable distancefrom the siding area: Thus, in accordance with standardtpractices,theyarious switches and signals are controlled via a code communicationsystem. Various control apparatus and code communictation apparaus areassumed to be located both in the control ofiice and in the fieldstations 6 and 8. The control office and field stations are shownconnected by line wires over which code communication is eifected.

The organization of track switch and signal control circuits locatedinthe field and including so-called safety circuits are assumed to be ofany of a number of standard types which are well-known in the art.Therefore, the present disclosure will be directed exclusively tocontrolofiice circuits and will show the manner in which the presentcontrol office circuits are used to selectively operate a codecommunication system which, in turn, selectively operates fieldapparatus. It must be pointed out, however, that the present controlcircuits can be used for controlling track switches and signals directlyas well as through the medium of code communication apparatus.

Control ofiice apparatus The trackway under the jurisdiction of thecontrol oifice is assumed to be controlled from a control panel havingva miniature track diagram and having control and indication apparatuslocated to correspond with the actual field layout. A portion ofthecontrol panel is shown in Fig. 2, and this panel section includesapparatus associatedwith control and indication functions relative tothe stretch of track and passing siding shown in Fig. 1.

In Fig. 2 a plurality of track switch control levers, such as levers 7WLand 9WL, are provided for manual selections of. the operating positionsto be assumed by track switches 7W and 9W. The switch levers are of atwo-position type, each position corresponding to a track switchposition. A plurality of signal control levers, such as levers 6GL and8GL, are provided for manual designations of stop and proceed operationsto be performed by signals 6R, 6LA, LB, 8L, 8RA and SRB. The signallevers are of a three-position type, i.e. a center position for stopcontrols, a left position for clearing signals governing trafiic to theleft, and a right position for clearing signals governing trafiic to theright.

Each set of track switch and signal control levers is located at therespective associated siding end location shown in the track diagram,and each set of levers has an associated start pushbutton, such aspushbuttons 6SPB andSSPB, for activating code communication apparatus totransmit control codes of selected characters. The code characters areselected, as will be described, through contacts of the various controllevers.

Indication lights of a standard type are provided to indicate trafiicand routing conditions. The lights 7NWE and 7RWE are selectivelyenergized in response to indication code characters originating at fieldstation 6 (see Fig. 1), and these'lights indicate the operated position(normal or reverse) of switch 7W. Similar lights 9NWE and 9RWE areprovided to indicate the condition of track switch 9W. Track lights 7TBand 9TB indicate, when lighted, occupancy by trains of the respectivedetector track sections 7DT and 9DT at the siding ends. Signalindication lights such as G (green) and R (red) are provided to indicateaspects displayed by the signals.

Since the'presentinvention provides for both manual andautomaticdesignations of route controls, a selector lever M81; is provided topermit the operator to manually select which mode of operation is to bein effect.

A plurality of indicator units IAN, 1N, 2N, 3N, 4N and 4AN' are providedto indicate both track occupancy and train description. Theseindicators, which will be described more specifically, are assumed to beof the type disclosed in the copending US. patent application of G. E.Marsh,Ser. No. 580,123 filed April 23, 1956. Each indicator is operableto a plurality of positions,

and, includes a movabletape which passes behind anopening. The tape hascharacters printed on it, and in the present disclosure thesecharacters. are assumed to b'e-itrain' identification numbers. Includedin each indicator unit is a lamp which will be energized to illuminatethe symbol then displayed only during occupancy of the correspondingtrack section. More specifically, indicators 1N, 2N, 3N and 4N arelocated in the track diagram at positions comparable to track sections1T, 2T, ST and 4T (see Fig. 1). The indicators IAN and 4AN are approachindicators which are operated by selector buttons to displaydescriptions which identify trains approaching the siding location. Theindicators 1N, 2N, 3N and 4N are associated, respectively, with tracksections 1T, 2T, 3T and 4T, and each indicator can be operated toindicate the occupancy of the associated track section and to indicatefurther a description of the occupying train. Since, as will bedescribed, descriptions stored by the indicators 1N and 4N are utilizedto condition route control circuits, these indicators can beconveniently termed control indicators.

As will be described later, transfer circuits are provided fortransferring train descriptions from one indicator to another as trainprogress. For example a train moving to the right would automaticallyadvance its description from indicator IAN to indicator 1N, then fromindicator IN to either indicator 2N or 3N (depending on routingconditions), and from indicator 2N or 3N to indicator 4N.

The initial storages of train descriptions in the approach indicators1AN and 4AN are effected by the operation of classification buttonslocated on the control panel below each approach indicator. It will beassumed that all trains moving to the right are identified on trainlists by odd numbers, while those moving to the left are identified byeven numbers. In this manner, the displaying of a train number by anindicator is also indicative of train direction. For the precedingreasons, the buttons associated with indicator IAN are odd-numbered,while those associated with indicator 4AN are evennum bered.

Other approach indicators AN and associated buttons are shown in Fig. 2in the vicinity of indicators 1AN and 4AN. These indicators AN areassumed to be provided for storing descriptions for trains moving fromthe illustrated passing siding locations to the next passing sidinglocations (not shown) in either direction.

The train description buttons associated with the approach indicator IANare arranged in two identical vertical rows. The buttons in each row areodd-numbered, ranging from 1 through 27. Similar rows of buttonsassociated with indicator 4AN are even-numbered, ranging from 2 through28. Thus, the arrangement shown permits the posting and storing of trainidentifications for trains listed as any number from 1 through 28. Thereason for having two rows of identically numbered buttons is to permitthe identification of a train as either superior or inferior. Thus, forexample, a train listed as No. 27 may be either a superior train or aninferior train. If it is a superior train, button 27 in the row headed Sis used for operating the storage indicator IAN, while button 27 in therow headed I is used if the train is inferior in classification. Thearrangement and utility of the train description buttons can bedescribed in greater detail following a description of the indicatordevices assumed for use in the present system.

As previously stated, the train descrpition storage means i is assumedto be a display indicator of the type disclosed in the US. patentapplication of G. E. Marsh, Ser. No. 580,123 filed April 23, 1956; but,it should be understood that any other suitable indicator may beemployed such, for example, as disclosed in the prior patent of Field etal., Patent No. 2,731,632 dated January 17, 1956. The present disclosurewill be confined, for simplicity, to general analogous description ofthe indicator disclosed in the above mentioned Marsh application.

- Each indicator includes a movable tape having inscribed thereonsuitable characters or symbols. The tape is operated to its dilferentpositions through a gearing by a motor which assumes diflerent positionsdependent upon the selective energization of six control wires. When thetape is located in any particular position in front of an opening orWindow, the symbol thereon can be plainly seen when an associated lampis energized to illuminate the symbol. In this way, the particularindicator having active information can be readily distinguished fromthose which are inactive.

It is, of course, readily understood that six control wires can beenergized and deenergized in sixty-four different combinationscorresponding to the Well-known binary Baudot code; but for basicreasons the first and last codes of a symmetrical table of such binarycode cannot be used. Also, the applicant Marsh in the above mentionedapplication desired to have his indicator readily adaptable for controleither over six control wires or over five code wires, the latter ofwhich would, of course, provide only thirty-two code combinations. Whenthe indicator is thus used with only five control wires andcorresponding structural characteristics, the first and last of saidthirty-two codes are unused. The net result is that for the indicatordisclosed in the Marsh application and asusmed to be here employed, onlysixty-one codes are actually usable.

However, in order to provide proper gear ratios and the like, it isnecessary that each indicator have sixtyfour actual physical positions.the positions have characters which are duplicates on the tape, and oneposition has a blank space on the tape. But in the present case, thereare sufficient positions of the indicator so that the duplicatepositions 1 and 17 of Figs. 5A and 5B are not shown as used. Likewise,the positions 33 and 49 of the indicator are duplicate positions andthey are not shown as used. Positions 31 and 63 are extra positions; andposition 64 cannot be employed but the application of any combination ofenergizations of the code wires causes the indicator to continue movingthrough such position without stopping. In other words, the physicalstructure is present but the tape does not have any symbol for suchposition and the indicator under normal usage does not stop in suchposition.

The six control Wires which are energized in difierent combinations torepresent codes lead to the commutator combinations in the indicatorwhich are constructed in such a way that the motor operates theindicator until the particular commutator positions are reached wherethe circuit to the motor is opened for the particular combination ofcontrol wires then energized. Although the indicator comprises sixcommutators and six cooperating movable disc-carried brushes, thecommutator elements and brushes are represented in this disclosure (seeFigs. 3B through 3F) as motor driven contacts 1 through 6. The front andback contact points correspond to the commutator elements, while themovable contact element corresponds to the disc-carried brush. Thestructure of the indicator is such that the contacts 1 through 6 of eachindicator are operable in the different contact making positionsdesignated in the chart of Figs. 5A and 5B. The letters F and Bdesignate contact making conditions under which front and back pointsare closed respectively.

When the indicator is in its position 1, for example, the positionsassumed by contacts 1-6 (Fig. 3B) shows position 29, in indicator llANare such that contacts 1-4 and 6 form closed front contacts and contact5 forms a closed back contact; in position 2, contacts 2-6 form closedfront contacts while contact 1 forms a closed back contact. Thus, thesequence of operation of the indicator contacts 1-6 to form closed frontand back contacts can be traced with reference to the code chart.

Referring to the indicator IAN in Fig. 3B, the equiv-' alent contacts1-6 are interconnected so that all front contacts are bussed togetherand all back contacts are bussed together. The movable contacts 1-6 arecon In view of this, two of nected to external wires which, as will bedescribed, can

be selectively energized individually or in combination. It must benoted here that the particular indicator assumed for use herein is analternating current device, and externally applied energy is assumed tobe of such character.

The back contact bus is connected to the motor and the latching relay LRthrough a rectifier 67. The arrangement of the rectifier and theinterconnecting wiring issuch that the motor is operated by alternatingcurrent energy while the relay LR is operated by rectified, orunidirectional current energy. The front contact bus can be; connectedto the motor through front contact 63 of relay LR and a limitingresistor 69. Whenever (BX) energy is applied to particular movableelements of contacts 1-6, the motor will be operated if any of thepositions of the particular contacts are such that energy can reach theback contact bus leading to the rectifier 67 and motor. Under suchconditions, relay LR is energized closing its front contact 68 to alsoprovide for the energi'zation of the motor from the front contact bus.As soon as'the motor operates the various contacts 1 through 6 topositions wherein the particular energized contacts break connectionswith the back contact bus relay LR is deenergized. This conditions thelatching structure (not shown) for positively engaging the tape drivinggear when the proper position is reached. But since the front contact 68cannot open until the latch has locked the gear, the motor is actuallyeffective to drive the gear into its locking position. The opening offront contact 68- then removes all energy from the motor whichimmediately comes to rest. Relay LR is slow-acting to allow time for themotor to nearly reach the desired operating position before attemptingto lock the tape and motor. Thus, once energized, the motor operates contacts l6 through various positional alignments until open-circuitconditions (back contact bus deenergized) are reached, at which timerelay LR releases to disconnect the motor from the front contact bus andto lock the tape and motor in position.

Since the application of energy to one or more control wires causes theindicator to operate until open circuit conditions exist in thecommutators, the present analogous representation requires that theindicator be operated until any of the movable elements of contacts 1-6connected to energized control wires must be operated to form open backcontacts (i.e. closed front contact positions). Thus, the characters Fin the present code chart of Figs. 5A and 5B indicate closed frontcontact conditions (open back contact conditions), and thereby alsodefine which of the six control wires must be energized to operate theindicator to its various positions.

The code chart also shows the characters inscribed on a movable tapewhich are to be displayed in each indicator position. representing trainidentification numbers. It is proposed, for example, that trainidentification numbers ranging from 1' through 28 be inscribed foridentifying twentyeight different trains. It is further proposed thattwo duplicate sets of train numbers be inscribed on each tape forreasons to be explained.

It can be seen from the code chart (Figs. 5A and 533) that indicatorpositions 1-32 call for front contact 6 to be closed, while back contact6 is closed for indicator positions 33-64. Thus, the condition ofcontact 6 (and theassociated control wires to be described) can be usedto differentiate between superior and inferior train classifications. Atrain identified as No. 1, for example, may be superior or. inferior inclassification. if the train is superior a description stored in anindicator for the train mustbe effected so-that the indicator isoperated to position,2 in which atape character 1 is displayed and frontcontact-2-6 are closed. If the train is inferior the storeddeseriptionmust be effected so that the indicator is op- In this case,the characters are numbers buttons headed S and I are provided (Fig. 2)for eachapproach indicator. The actuation of button 1 in rows will, aswill be described, operate indicator 1AN to its position 2 (Fig. 5A);similarly, the actuation of button 1 in row I will operate indicator IANto its position 34 Regardless of which button 1 is operated, indicatorlAN will display a character 1, but the contact Thesame mode ofoperation applies to the indicator 4AN and (Fig. 5B).

make-ups in the indicator differ in the two cases.

its associated train classification buttons.

The assignments of specific train numbers to indicator positions (Figs.5A and 5B) is based on several requisites to be described. First, eachsuperior train number must be assigned to an indicator position in whichfront contact 6 is closed, While each inferior train number must beassigned to a position in which back contact 6 is closed. Position 64 ofthe indicator is, as described unsuitable for use. Positions 1 and 17are identical insofar as contact make-ups are concerned, and positions33 and 49 are similarly identical. the present disclosure positions 1,17, 33 and 49 are not used, thereby eliminating the need for furtherduplicating train numbers. The elimination of positions 1, 17, 33, 49and 64 from use leaves fifty-nine positions for use in identifyingtrains. For symmetry, however, positions 31, 32, 33 and 63 arearbitrarily eliminated fromuse, so that fifty-six positions are finallyused for train identification. Thus, twenty-eight superior trains andtwenty-eight inferior trains are provided for.

to the left in Fig. 1) and fourteen odd-numbered trains (those moving tothe right) can be accommodated. For this reason each vertical row oftrain classification buttons (Fig. 2) comprises fourteen buttons.

Referring to Figs. 2, 3A and 3B, the operation of the approach indicatorIAN to store and display a train description can be described. Thesuperior train description buttons 1-27 (row S in Fig. 2) and theinferior train description buttons 1-27 (row 1 in Fig. 2) are shown, inpart, in Fig. 3A.

of the buttons because such arrangements will be obvious from theportions shown.

Contacts of the various train description buttons are connected tobusses in a predetermined manner for selectively energizing a pluralityof code relays CR1, CR2,

CR3, CR4, CR5 and CR6. These code relays are usedto control theindicator IAN to display train numbers corresponding with the numbers ofthe buttons operated.

The manner in which the code relays CR are operatedcan be seen followinga description of the controlcircuits for indicator IAN.

Control energy (BX) for indicator IAN is supplied through a frontcontact of a button-operated transfer relay CTN. Contact 70 is connectedto a bus whichinterconnects front contacts 71-76 of relays CRl-CRG,

respectively. The back contact points of contacts 71-76 to its position29 (see Fig; 5A) in which front contacts To simplify In this manner,fourteen even-numbered trains (those moving It will not be necessary toshow the circuit arrangements including contacts of all 2 and 6 areclosed. In this condition the train description stored by the indicatoris for a train No. 27 having a superior classification.

Assume that the dispatcher wishes to store a description for a train No.25 of inferior classification. The dispatcher presses the inferior traindescription button 25, closing contacts 79, 80 and 84 of the button,causing the energization of relays CR1, CR3 and CTN, respectively. Frontcontacts 70, 71 and 73 of the respective relays CTN, CR1 and CR3 closeto apply (BX) energy to contacts I and 3 of indicator IAN. Since backcontact 3 of indicator IAN is closed, energy is supplied to the motorand to the latching relay LR in indicator IAN through the back contactbus, the complete circuit to (NX) energy extending from the motorthrough wire 81 and front contact 82 of relay IATN. Relay LR picks up torelease the locking of the indicator gearing, and the motor operates todrive contacts I-6 and the movable tape (not shown) to the indicatorposition 59 (see Fig. B). When indicator position 59 is approached backcontact 1 opens (back contact 3 being previously opened) to deenergizerelay LR and the direct motor made, and at this time (BX) energy appliedto contact 'I from the code relays passes through the front contact bus,front contact 68 of relay LR and the limiting resistor 69 to the motor.The motor is thereby driven at a reduced energy level until the latchingstructure of relay LR is able to drop into the slot associated withposition 59, at which time contact 68 of relay LR opens to completelydeenergize the motor. The slow-release characteristics of relay LR areuseful in holding the latching structure (not shown) picked up for atime so that it does not ride on the indicator gearing and produce adrag.

From the foregoing description it can be seen that the connectionbetween the code relay CR and indicator IAN contacts is such that theindicator is operated to a position wherein its contact alignment(fronts or backs closed) must be identical to the alignment of the coderelay contacts (fronts or backs closed). Thus, if the indicator IAN isto store a description for a superior train No. 1, the indicator must beoperated to indicator position 2 (Fig. 5A) in which front contacts 2-6of the indicator are closed. To attain this condition front contacts72-76 of relays CR2-CR6 must be closed to call for proper indicatoroperations. Thus, relays CR2- CR6 must be energized by the superiortrain button 1, and contacts of button 1 are included in each pick-upbus for those relays. The other train description buttons also havecontacts included in the pick-up busses for relays CR1-CR6 in accordancewith the principles described above and in view of the code chart (Figs.5A-5B).

Every time a train description button is operated relay CTN isenergized, since a contact of each button (such as 84 of button isconnected to the pick-up bus for relay CTN. Relay CTN closes its frontcontacts 70 and 83 to provide, respectively, energy (BX) for operatingthe indicator IAN and stick energy for any picked-up code relays CR.When a selected button is released, relay CTN and selected CR relays arereleased, but energy (BX) is removed from the control wires forindicator IAN before the code relays CR are released. In this manner, anindicator position cannot be changed because of possible differences inthe release times of relays CR.

Similar circuits for operating the approach indicator 4AN are indicatedin block form in Fig. 3E. Such circuits are assumed to include coderelays CR, a transfer relay CTN and train description buttons foreven-num bered .trains (see Fig. 2).

Train descriptions stored in the approach indicators- IAN and 4AN can betransferred by circuit means to be described into the indicators IN and4N, from which descriptions can be transferred to the remainingindicators 2N and 3N. The transfer of descriptions can take place inboth directions between indicator 1N and indicators 2N and 3N, andsimilar transfers between indicator 4N and indicators 2N and 3N arepossible. Without describing specifically the various transfer circuitmeans at this time attention can be given to the interconnecting wiringbetween the various indicators while making general reference to themode of operation of the transfer circuits.

In Figs. 3A and 3B, the contacts I-6 of indicator IAN are connected torespective corresponding contacts in the indicator IN through contactssuch as 85 and 86 of relays IWS and ITN, respectively. Relay IWS is adirectional stick relay which is operated to prevent transfers fromindicator IN to indicator IAN, while relay ITN is a transfer relayoperable to permit storage transfers from indicator IAN to indicator 1N.Assuming that relay IWS is deenergized and relay ITN is energized,indicator 1N can be operated whenever relay IATN is dropped away.Specifically, when relay IATN is dropped away,

its back contact 87 closes to apply (BX) energy to the front contact busin indicator IAN through wire 88. This energy is applied through any ofthe contacts 1-6 in indicator IAN which are closed in their frontcontact positions. Indicator IAN is then operated by the selectiveenergization of the interconnecting wires through corresponding closedback contacts in the indicator. In other words, the operation ofindicator IAN to a par ticular position is identical to the previouslydescribed operation of indicator IAN to a position called for by thealignment of contacts of the code relays CR. In this manner, whenso-called read-out energy (BX) is applied to an indicator, a secondindicator can be operated to a position corresponding to the position ofthe first indicator. In order to preclude possible operations of anyindicator to which read-out energy is applied for operating a secondindicator, the motor circuit of the first indicator must be interrupted.For this reason, when read-out energy (BX) is applied to the indicatorIAN,

- the motor circuit for the indicator is opened by front contact 82 ofrelay IATN.

Referring to Figs. 3A-3F, the indicator IN is connected to indicator 2Non a contact-to-contact basis so that operations of either indicator bythe other can be effected. Contact 1 in indicator 1N, for example, isconnected to contact 1 in the indicator 2N by wire 89, front contact ofa transfer relay ZTN, and from contact 91 of a track switch indicationrelay 7NWK. The remaining contacts in the two indicators areinterconnected in a similar manner. By the same token, the contacts I-6in indicator IN are connected to corresponding contacts in indicator 3Nby circuits such as one including wire 89, front contact 90 of thetransfer relay ZTN, wire 92, and front contact 93 of a track switchindication relay 7RWK. Read-out energy for operating either indicator 2Nor 3N is applied to the front contacts of indicator IN by front contact94 of a read-out relay IRO. Relay 1R0 also acts to open the motorcircuit for indicator 1N at back contact 95 during read-out operations.When read-out operations are taking place from indicator 2N to indicatorIN, read-out energy is applied to indicator 2N by front contact 96 ofanother read-out relay'ZRO, and back contact 97 of relay 2R0 Opens themotor circuit for indicator 2N during read-out operations. Similarly,transfers of storages from indicator 3N to indicator 1N are effected bythe operation of a read-out relay 3R0 which applies read-out energy toindicator 3N through its front contact 98, and opens the motor circuitfor indicator 3N at its back contact 99. Transfer operations betweenindicators 1N 2N and 1N-3N are dependent upon the position of trackswitch 7W (Fig. 1)

'11 and other-considerations which will be described later. Descriptionsstoredby indicator 2N can. be transferred tothe indicator 4N throughsimilar circuit. operations. The contacts 16 in indicator 2N areconnected to corresponding contacts in indicator 4N by circuits such asthat including front contact 100 of a track switch indication relay9NWK, front contact 101 of a transfer relay 3TN and wire 102. Read-outenergy for such a transfer is provided by front contact 96 of relay 2R0.The transferring of descriptions from indicator 3N to indicator 4N areeffected through circuits which interconnect respec tive indicatorcontacts, such as the circuit including front contact 103 of the trackswitch indication relay 9RWK, wire 104, front contact 101 of relay 3TN,and wire 102. Read-out energy for such transfers is applied to theindicator 3N by front contact 98 of the read-out relay 3R0.

Transfer operations in which descriptions stored by indicator 4N are tobe transferred to either indicator 2N or 3N are accomplished by way ofsimilar interconnecting circuits. Read-out energy in such cases isapplied to the contacts of indicator 4N by front contact 105 of readoutrelay 4R0. Back contact 106 of relay 4R0 opens the motor circuit forindicator 4N during read-out operations.

The contacts 1-6 in indicator 4N are connected to corresponding contactsand indicator 4AN (see Figs. 3D and 315) by circuits such as thatincluding front contact 107 of a transfer relay 4TN, wire 108 and backcontact 109 of a directional stick relay 4E8. Since it is assumed thatread-out operations can be effective on a single direction basis, fromindicator 4AN to indicator 4N, the read-out energy is supplied in suchcases by back contact 110 of a transfer relay 4ATN. Undesirable operations of indicator 4AN during read-out operations are precluded by theopening of front contact 111 of relay 4ATN.

A description can now be given of the various relays and circuit meansnecessary to provide for the transferring of train descriptions betweensuccessive indicators- It is assumed in the present disclosure that codecommunication apparatus is employed to connect the control oflice withthe various field stations located at the passing siding. The codecommunication system can be of any of a number of well-known types andwill not be described at this time except with reference to indicationrelays which are usually employed in conjunction with such codecommunication systems. Track occupancy indication relays 1TK, ZTK, 3TK,4TK, 7DTK and QDTK are shown in Figs. 3A3F. These relays are assumed tobe of the magnetic stick type and areselectively operated in response toindication code characters transmitted by the code communicationapparatus from the various field stations. Each track indication relayTK is assumed to be picked up when an indication code indicates that theassociated track section is occupied, and these relays are dropped awaywhen the associated track sections are indicated as being unoccupied.Also shown in the drawings are track switch indication relays 7NWK,7RWK, 9NWK and 9RWK. These relays are also of the magnetic stick typeand are responsive to selected indication codes for indicating thepositions assumed by respective associated track switches. Relay 7NWK,when picked up, indicates that the operated position of track switch 7Wis normal, or arranged for moves straight through the stretch of track.Relay 7RWK, when picked up indicates that switch 7W is in its reverseposition for routing trafiic into or out of the passing siding. Relays9NWK and 9RWK function in similar manners to indicate the respectivenormal and reverse positions of track switch 9W.

A transfer relay IATN is provided for permitting transfersof traindescriptions from the code relays CRl-CR6 to indicator IAN. Relay lATNis normally energized by. a circuit includingback contact 112 of relay1TK whenever'track section II is indicated as'being unoccu pied; Asimilar transfer relay 4ATN is provided for permitting transfers oftrain descriptions into indicator 4AN. from similar code relays CR. Thisrelay 4ATN is also operated in accordance with track occupancyconditions, and its pick-up circuit includes back contact 114 of thetrack indication relay 4TK. A transfer relay 1TN is provided forpermitting transfers of train descriptions from indicator IAN toindicator IN. This relay is responsive to track occupancy conditions andcan be energized by front contact 112 of relay 1TK. A similartransferrelay for permitting transfers of train descriptions from indicator 4ANto indicator 4N is provided; This relay is responsive to the conditionof track section 4T and has a pick-up circuit including front contact114 of relay 4TK and wire 115.

A transfer relay ZTN is provided for permitting transfers of traindescriptions from indicator IN to either indicator 2N or 3N, andconversely. Relay ZTN has a plurality of pick-up circuits, one includingfront contact front contact 123 of a directional stick relay 3W8 orfront contact 124 of a directional stick relay 2WS. A

similar transfer relay STN is provided for permitting transfers fromindicator 4N to either indicator 2N or 3N, and conversely. Relay 3TN hasa plurality ofpickup circuits, one including front contact 125 of aread-outrelay 4R0 and wire 126, the other pick-up circuit includingfront contact 127 of relay 4TK, wire 128, either front contact 129 of acontrol relay 3-4C or front contact- 130 of a control relay 24C and wire126. A stick cir cuit for relay STN includes its front contact 131 andeither front contact 132. of a directional stick relay 3E8 or frontcontact 133 of a directional stick relay 2E8.

As previously stated, each of the indicators 1N, 2N, 3N and 4N haveassociated read-out relays 1R0, 2R0; 3R0 and 4R0 for effecting transfersof train descrip: tions from respective associated indicators to otherindicators. Relay 1R0 can be energized by either of two pick-upcircuits. One pick-up circuit includes front contact 134 of relay ZES,wire 135 and front contact 136 of a control relay 1-2C. The otherpick-up circuit includes front contact 137 of relay 3E8, wire 138, andfront contact 139 of a control relay 13C. Relay 1R0 also has a stickcircuit including its front contact 140 and front contact 141 of relayITK. Relay 4R0, which is comparable to relay 1R0, is provided with twopick-up circuits. One circuit includes front contact 142 of adirectional stick relay 3W8 and front contact 143 of a control relay4-30 The other pick-up circuit includes front contact 144 of adirectional stick relay ZWS and front contact 145 of a control relay42C. Relay 4R0 has a stick circuit including its front contact 146-,wire 147 and front contact 148 of relay 4TK. The read-out relay 2R0 hastwo pick-up circuits and a stick circuit. One pick-up circuit includesfront contact 149 of control relay 2-1C, and Wire 1511, and the otherpick-up circuit includes front contact 151 of control relay 2-4C andwire 150. The stick circuit for relay 2R0 includes its front contact 152and front contact 153 of relay ZTK. Similar pick-up and stick circuitsare provided for relay 3R0. One pick-up circuit includes front contact154 of control relay 31C and wire 155, and the other pick-up circuitincludes wire 155 and front contact 156 of a control relay 34C. Thestick circuit for relay 3R0 includes its front contact 157 and frontcontact 158 of relay 3TK.

A plurality of directional and directional stick. relays.

Relay ZTN is provided with a stick cir-- cuit including its frontcontact 121, wire 122, and either are provided for detectingdirectionsof train movements, and theserelays function to permittransfers of train descriptions between indicators on a directionalbasis in accordance with train direction. A directional relay 1-2D and adirectional stick relay 2E8 are provided to detect trains moving fromtrack section 1T into track section 2T. Relay 1-2D has a pick-up circuitincluding front contact 160 of relay lTK, wire 161 and back contact 162of relay 2TK. Thus, relay 1-2D can be energized only when track sectionIT is occupied, but track section 2T is unoccupied. The companiondirectional stick relay 2ES has a pick-up circuit including frontcontact 163 of relay 2TK and front contact 164 of relay 1-2D. Relay 2ESalso has a stick circuit including its front contact 165 andfrontcontact 163 of relay 2TK. Thus, when a train occupies track section1T, relay lTK is picked-up closing its front contact 160 to energizerelay 1-2D. As the train advances to occupy both track sections .lT and2T, relay 2TK picks up, opening its back contact 162 to deenergize relay1-2D and closing its front contact 163 to pick-up and stick relays 2ES.The picking up of relay 2ES is possible because relay 1-2D (and all ofthe other directional relays D) is assumed to be slow-acting inreleasing its armature; thus, front contact 164 of relay 1-.2D remainsclosed in the pick-up circuit for relay -2ES long enough to permit relay2E8 to be picked up.

Directional relay 1-3D and directional stick relay 3ES detect trainmovements from track section IT to track section 3T in a similar manner.Relay 1-3D has a pick-up circuit including front contact 166 of relay1TK, wire 167 and back contact 168 of relay 3TK. Relay 3ES has a pick-upcircuit including front contact 1690f relay 3TK and front contact 170 ofrelay 1-3D; and a stick circuit for relay 3ES includes its front contact171 and front contact 169 of relay 3TK.

Directional relay 4-2D and direction stick relay 2W8 detect trainmovements from track section 4T into track section 2T, while similarrelays 4-3D and 3W8 detect train movements from tracksection 4T intotrack section ST. The pick-up circuit for relay 4-2D includes frontcontact 172 of relay 4TK, wire 173, and back contact 162 of relay 2TK.Relay 2W5 has a pick-up circu it including front contact 163 of relayZTK, front contact 174 of relay 4-2D and wire 175; a stick circuit forrelay 2WS includes its front contact 176, wire 177 and front contact 163of relay ZTK. Relay 4-3D has a pick-up circuit including front contact178 of relay 4TK, wire 179, and back contact 168 of relay 3TK. Relay 3W8has a pick-up circuit including front contact 169 of relay 3TK, frontcontact 180 of relay 4-3D, and wire 181; a stick circuit for relay 3WSincludes its front contact 182, wire'183, and front contact 169 of relay3TK. Two other directional stick relays 1W8 and 4E8 are provided fordetecting trains moving from either track section 2T or 3T into tracksections IT and 41' (i.e. trains leaving the siding location). Relay IWSdetects leaving trains moving to the left into track section 1T, whilerelay 4ES detects leaving trains moving to the right into track section4T. Relay 1WS has a pick-up circuit in cluding either front contact 184of relay ZWS or front contact 185 of relay 3WS, wire 186, and frontcontact 187 of relay 1TK; a stick circuit for relay 1W5 includes itsfrontcontact 188 and front contact 189 of relay ITK. Relay 4E8 has apick-up circuit including either front contact 190 of relay 2E8 or frontcontact 191 of relay 3E8, wire 192, and front contact 193 of relay 4TK;a stick circuit for relay 4ES includes its front contact 194 and fromcontact 195 of relay 4TK.

-As described earlier, superior and inferior train descriptions differin that an indicator storing such descriptions must be operated to aposition wherein its frontcontact 6 is closed if the description issuperior, and its back contact 6 is closed if the description isinferior. Transfers, or read-out operations, between in-.

dicators will'therefor'e result in the energization ofthe code wireconnecting thecontacts 6 in respective indicators. For example, theillustrated condition of indicator IAN is that which the indicatorassumes when storing a description for a superior train No. 29 (see Fig.5A).

When read-out energy (BX) is applied to indicator IAN by contact 87 ofrelay IATN through wire 88, front contacts 2 and 6 in indicator IAN areclosed. If relays IWS and 1TN are in the proper positions, (BX) energyis applied by obvious means to contacts 2 and 6 in indicator 1N, andwill operate the indicator 1N accordingly. It must be noted, however,that contacts 2 and 6 of indicator 1N are also connected to contacts 2and 6 in indicator 2N (or 3N) by obvious circuits including wires 200and 201. Since read-out operations between indicators 1N and 2N (or 3N)in either direction are accomplished via wires such as 89, and 201, itfollows that wire 201 will always be connected to (BX) energy during atransfer operation involving indicator 1N, provided that a descriptionbeing transferred is for a superior train. In order to detect superiortrain classifications a decoding, or superiority detection, relay IDC isprovided. Relay 1DC is connected to a rectifier 202 which is, in turn,connected to the secondary winding of a transformer 203. The primarywinding of transformer 203 is connected at one terminal to (NX) energyand at the other terminal to wire 201. Thus, when wire 201 is connectedto (BX) energy during transfers of superior train descriptions, relay1DC is picked up. A similar decoding relay 4DC is provided, and isconnected through a rectifier 204 and transformer 205 to a wire 206which is connected to contact 6 in indicator 4N. As will be seen, theprimary function of relay .lDC is to detect superior classificationdescriptions for trains entering the siding location (Fig. 1) from tracksection 1T, while relay 4DC performs similar detections of superiortrains entering via track section 4T.

Since situations can arise wherein two opposing trains entering thestretch of track have identical superiority classifications, it may bedesirable to give'priority to one train on a directional basis. Thepresent system is arbitrarily arranged to give a directional superiorityto trains.

moving from left to right in Fig. 1. The detection of conditions whereintwo trains of the same classification are present concurrently isperformed by a directional priority relay DPR. A pick-up circuit forrelay DPR extends from through front contact 207 of relay.

1TN, wire 208, contact 209 of relay lDC, the upper or lower windings ofrelay DPR, wires 210 or 211, contact 212 of relay 4DC, and front contact213 of relay 4TN, to trains are being transferred into indicators 1N and4N,

contacts 207 and 213 of relays ITN and 4TN, respectively, close in thepick-up circuit for relay DPR. If the train classifications areidentical, relays llDC and 4DC will both be either energized (superior)or deencrgized (inferior). Under such conditions, contacts 209 and 212of relays IDC and 4DC, respectively, will assume comparable positions,energizing either the upper or lowertrack section 1T. Relays 4-2C and4-3C call for routes from track section 4T to respective track sections2T and 31, while relays 2-4C and 3-4C call for routes from respectivetrack sections 2T and 3T to track section 4T.,

Since route controls are assumed to be effected via code. communicationapparatus, it will be shown later that...

Whenever two train descriptions for opposing.

operations of the control relays C activate control office-- codecommunication apparatus and select the characters of control codes to betransmitted to the field stations 6 and '8 (see Fig. 1). For example,the energization of relay 12C will result in the transmitting of controlcodes calling for track switch 7W to be operated to its normal positionand calling for the clearing of signal 6R; in

other words, calls are made to establish a route for atrain moving fromtrack section IT to track section 2T.

Before describing the circuits for operating the control relays C itmust be stated that the present system isarranged to operate inaccordance with an arbitrary premise that any train will be normallyrouted straight through the stretch of track rather than via the siding.Under automatic operating conditions, therefore, a train Will be routedthrough via the passing siding when a concurrently present opposingtrain of a superior classification is detected.

The control relay 1-2C is energized whenever a train is to be routedfrom track section 1T into track section 2T. This relay has a pick-upcircuit including back contact 215 of relay llWS, front contact 216 ofrelay lTN, back contact 217 of relay 7DTK, wire 218, back contact 219 ofrelay ZTK, wire 220, and back contact 221 of relay 4DC. Thus, relay 12Ccan be energized whenever relay lTN is energized in response to thedetection of a train entering track section 1T, provided that tracksection 2T is not occupied and/oran opposing train of a superiorclassification is not detected. In cases where two opposing trains ofthe same classification are present, relay DPR is operated as previouslydescribed closing its front contact 222 to by-pass back contact 221 ofrelay 4DC in the previously described pick-up circuit for relay 12C.Connected in parallel with contacts 221 and 222 of relays 4DC and DPR,respectively, is a front contact 223 of a timing relay 1TB. The functionof the timing relay 1TE is to measure a time interval during which relay1-2C can be deenergized by the detection of an opposing superior train.in other words, the energization of relay 1-2C to establish a route fora train results in the starting of the timer 1TB by the closing of frontcontact 224 of relay 12C in a circuit including wire 224a. Until thetimer 1TE completes its timing operation to close its front 223, relay12C can be deenergized by the opening of back contact 221 of relay 4DCin response to the detection of a superior opposing train.

Routes from track section 1T to track section 3T are called for by theenergization of control relay 13C. This relay is normally operated onlywhen a route to track section 2T is not available because oftrackoccupancy, or because of conditions wherein a train which would benormally routed to track section 2T is opposed by another train having asuperior classification. Under conditions wherein relay 13C is to beoperated -because of track occupancy conditions, the relay has a pick-upcircuit including back contact 215 of relay 1W8, front contact 216 ofrelay lTN, back contact 217 of relay 7DTK, wire 225, front contact 226of relay ZTK, and back contact 227 of relay 3TK. If track section 2T isnot occupied, back contact 226 of relay 2TK in the previously describedpick-up circuit is closed, and the piclcup circuit is altered to includeback contact 228 of relay DPR, wire 229, and front contact 230 of relay413C.

The setting up of routes for trains entering the stretch of track fromthe opposite direction is controlled by relays 4-23 and 43C. The pick-upcircuits for these relays have a common portion including back contact231 I of relay 4E5, wire 232, front contact 233 of relay 4TN and backcontact 234 of relay 9DTK. Under normal conditions, relay 44C isoperated by a pick-up circuit including the described portionandextending through wire 235, back contact 236 of relay DPR, back contact237'of relay2TK, and back contact 238 of relay 1DC.

Thispick-up circuit isdependent upon the occupied-con- Associated withrelay 4-2C is a timing relay 4TE which is operated by the closing offront contact 23? of relay 4-2C. As in the case of the previouslydescribed'relay 1TE, relay 4TE measures a time interval during whichrelay42C can be deenergized in response to the detection of an opposingsuperior train. If relay 4TB completes a timing operation holdingcircuit for relay 4-2C is established through front contact 24s of relay4TB, wire 241, and backcontact 242 of relay 2TK. Relay 43C, on the otherhand, can be picked up in response to the entrance of a train into tracksection 4T from the right'by circuits including the common portionshared with relay 4-2C, wire 283, back contact 284 of relay 3TK,contact285 of relay 2TK, front contact 286 of relay IDC and frontcontact 287 of relay DPR. A pick-up circuit for relay 43C can becompleted when track section 2T is occupied by another train and/or whentrack section 2T is unoccupied but an opposing train of either asuperioror equal classification is detected.

Relays 1-2C, 13C, 4-2C and 4-3C are capable When operated of routing anincoming train from respective track sections IT or 4T into either tracksection 2T or- 3T. When a train has been routed into either tracksection 2T or 3T, it is necessary to operate a second route controlrelay C to call for track switch and signal operations which will permitthe train to leave the siding train as indicated by relay 2WS must befrom right to left in the track diagram. The remainder of the pick-upcircuit for relay 3-1C includes back contact 246 of relay 21C, wire 247,and front contact 248 of relay 3W5. This pick-up circuit can beeffective only when track section IT is unoccupied and the direction oftrain movement is again from right to left in the track diagram.

The controlling of routes for trains occupying either track section 2Tor 3T, when such trains have destinations involving track section 4T,are-controlled by the respective relays 2-4C and 34C. Relays 254C and 34C have pick-up circuits including a common-portion which includes backcontact 249 of relay 4TK and Wire 250. Thus, both relays are dependentupon the-unoccupied condition of track section 4T. The remainder of thepick-up circuit for relay 24C includes wire 251 and front contact 252 ofrelay 2E8. The remainder of the pick-up circuit for relay 3-4C includesback contact 253 of relay 2-40, wire 254, and front contact 255 of relay3E8. In order for either pick-up circuit'for the respective relays to beeifective, therefore, the direction of movement of a train must be fromleft to right in the track diagram, as indicated by the condition ofeither relay 2E8 or 3E5.

Code communication apparatus of well-known types. The type selected forillustration,

however, is assumed to be of the type disclosed in the US. Patent No.2,399,734 to W. D. Hailes 'et al., dated May 7, 1946. This patentdiscloses a code communication system which is operable to transmitselected control codes from a control oifice to field stations and totrans- 17 mit selected indication codes from the field stations to thecontrol oflice. Coding and decoding circuits translate control codes forselectively operating track switches and signals, and translateindication codes for operating indication relays in the control ofiice.

Relying on the above patent to Hailes et al. for a complete descriptionof code communication operations, the present disclosure will be limitedto more general descriptions and will show the manner in which thepresent invention can be used in conjunction with the system.

In Fig. 6, the control ofiice portion of the code communication systemdisclosed in the above Hailes 'et al. patent is shown in partial detail.Only those elements necessary to show cooperation with the presentinvention are shown, and the various elements can be readily associatedwith their counterparts in the Hailes et al. disclosure.

The apparatus includes location relays LC and start relays CH which areassociated with respective field stations (see Figs. 1 and 2). Relays6LC and 6CH are associated with field station 6 and the signalingdevices at the left end of the siding. Relays 8LC and 8CH are associatedwith field station 8 and the apparatus at the right end of the siding.In addition, the various LC and CH relays are also associated with thecontrol levers (Fig. 2) and other apparatus (Figs. 3A-3F) which are usedto selectively control each field location.

Whenever a start relay CH and its associated location relay LC areenergized, the code communication system is activated in the mannerdescribed in Hailes et al. A bank of stepping relays 1V-6V and LV areactuated, and these relays operate in a sequence (or cycle) during whicha plurality of step channels are formed by a network of stepping relaycontacts. Energy is supplied through the stepping contact network tostep terminals in sequence, and these terminals are connected bycontacts of the various LC relays to control levers or relays which, inturn, are capable of selectively energizing coding relays LS and SL.Relays LS and SL, in turn, operate to apply distinctive code charactersto the line circuit connecting the control office and, the fieldstations.

Aspreviously described, the control panel (Fig. 2) includes a manualselection lever MSL which can be operated to selectively determinewhether manual or automatic controls are to be exercised to route trainsthrough the stretch of track and passing siding (Fig. 1). If automaticcontrols are to be effected the lever MSL is positioned to the left asshown, and contacts of the lever MSL (Fig. 6) connect the codecommunication apparatus to networks of contacts associated with theroute control relays C. When positioned to the right, contacts of leverMSL connect the code communication apparatus to a network of trackswitch and signal control levers, and to start pushbuttons SPB.

The switch control lever 7WL, the signal lever 6GL and. the start button6SPB (Fig. 2) are provided to control the track switch 7W and signals6R, 6LA and 6LB at field station 6 (Fig. l). The route control relays1-20, 1-3C, 2-1C and 3-1C (Figs. 3A-3F) are provided to exerciseautomatic controls over the signaling devices at field station 6. Thus,the start relay 6CH (Fig.

6) and the associated location relay 6LC can be op-.

erated in a plurality of ways to cause the transmission of control codesto field station 6.

Under automatic conditions relay 6CH is connected by contact 257 oflever MSL and back contact 258 of a cut-off relay CF to a parallelcombination of control relay C contacts such as front contact 259 ofrelay 3-1C. Thus, whenever relay 1-2C, 21C, 1-3C or 3-10 is energizedrelay 6CH is picked-up. Once energized, relay 6CH is held by a stickcircuit including its front contact 260 and back contact 261 of relay6LC. The subsequent closing of front contact 262 of relay 6CH con nectsthe winding of relay 6LC into a chain circuit which receives energy viaa wire 263. As disclosed in the above "18. patent to Hailes et al.,relay 6LC picks up and is held by a stick circuit (not shown) which iseifective for the duration of a control'code transmission cycle. Theenergization of relay 6LC activates the code communication apparatus,causing the stepping relays 1V-6V and LV to operate in sequence. Whenrelay V1 picks up, its front contact 264 closes to apply energy to astep terminal identified by the character (1). As relays V2-V6 areoperated in sequence other step terminals (2)-(6) are energized insequence. The step terminals (1)-(6) are connected through contacts suchas 265 of relay 6LC to contact networks which selectively apply energyto busses for picking up the code. determining relays LS and SL.

As described in the above Hailes et al. patent the first step or stepsin each control cycle are used to transmit station call codes whichselectivelyrender the apparatus at a selected field station responsiveto codes transmitted on succeeding steps. and (2) are not shownconnected, but are assumed to be connected in a predetermined manner tothe LS and SL busses. Step (3) is assigned here for track switchcontrol, and steps (4) and (5) are assigned to signal controls. Thus,when front contact 265 of'relay 6LC is closed, step (3) terminal isconnected selectively to either. the LS or SL bus through contact 266 oflever MSL, and either contact 267 of the switch control lever 7WL' orcontacts 268, 269, 270, 271, 272 and 273 of the respective'controlrelays 3-1C, 1-3C, 2-1C and 1-20. The assumption is made that if switch7W is to be operated to its normal position, relay LS is to beenergized'to cause the transmission of a particular code character,'

of relay 6LC. Since the routes associated with relaysj 1-2C and 2-1C,for example, both call for the normal positions of track switch 7W, theenergization of either relay will connect relay LS to step terminal (3)}If relay 1-2C is energized the circuit from step terminal (3) to relayLS can be traced through front contact 265 of relay 6LC, contact 266 oflever'MSL, back contact 268 of relay 3-1C, back contact 269" of relay1-30, and front contact 271 of relay 1-2C. With the exception of frontcontact 271 of relay 1-2C, the' same connection would be made if relay2-1C were energized instead, =resulting in the closing of front contact270 of relay 2-1C in the network.

If either route control relay 1-3C or 3-1C is operated, I

the routes defined by these relays require track switch 7W to beoperated to its reverse position. Therefore, on the third step relay SLmust be connected to step terminal (3). It should be evident that suchconnections are made when either front contact 268 of relay 3-1C orfront contact 269 of relay 1-3C are closed.

terminal and the LS and SL relay busses is arranged to preventconflicting route calls to be made. If either relay 1-2C or 2-1C isenergized at the same time as either relay 1-3C or 3-1C, a completecircuit to either relay LS or SL from step terminal (3) cannot be made.

The fourth step (4) is assigned, insofar as field station For thisreason step terminals (1) The connecting network described between step(3) (Fig. 1). The signal 63 has two heads for governing both of thedivergent routes over switch 7W. The manner in which the signalmechanisms are selectively controlled is a functionof switch positionand, although not shown in the present disclosure, is well-known in theart. The routes defined by control relays 1-2C and 1-3C both requirethat signal 6R be cleared. Thus, on the fourth step, step terminal (4)is connected to the SL or LS relay busses by circuits including frontcontact 274 of relay 6LC, left contact 275 of selection lever MSL, andcontacts 276 and 277 of the respective relays 1-3C and 1-2C. If eitherrelay 1-2C or 1-3C is energized relay LS is connected to step terminal(4), resulting in the transmission of a signal-clearing code character.If neither relay 1-2C nor 1-3C is energized, no route to the right overswitch 7W is presumably called for and relay SL is connected to step (4)terminal. In the latter case, a stop control code is transmitted on thefourth step. i i

If manual operations are in effect, lever MSL is positioned to the right(Figs. 2 and 6), and step terminals (3), (4) and (5) are connected bycontacts such as right contacts 266 and 267 of lever MSL through contacts of the switch and signal control levers to the LS and SL relaybusses. Contact 267 of switch lever 7WL, for example, selectivelyconnects the LS and SL busses to step terminal (3), while contact 278 ofthe signal lever 6GL selectively connects the LS and SL busses to stepterminal (4). At the same time, the starting of the code communicationsystems under manual conditions is such that relay 6CH must be energizedby the closing of contact 279 of the start button 6SPB, since contact257 of lever MSL is closed to the right.

Since manual operations are well-known, and are described in the aboveHailes et al. patent, no further description will be given here. Itshould also be evident that manual and automatic controls for thesignaling devices at field station 8 (Fig. 1) are effected in a similarmanner. The present disclosure (Fig. 6) shows the circuits necessary tooperate the start relay SCH and location relay 8LC, but does not showcircuit connections from the step terminals (1 )-(6) to various leverand control relay contacts through contacts of relay 8LC such as 280.

Under manual operating conditions, each actuation of a start button suchas 6SPB energizes a start relay such as 6CH. The start relay is held bya stick circuit until the associated location relay LC picks up to startcode transmissions. In Fig. 6, when relay 6LC picks up, its back contact261 opens the stick circuit for relay 6CH, denergizing the latter relay.If relay 6CH is held energized by its pick-up circuit, however, anothercode cycle is started after the completion of the first. Pushbuttonoperations to obtain starts are usually brief and do. not close thepick-up circuit for a start relay CH for a length of time sufiicient tocause the transmission of a plurality of control code cycles. Underautomatic conditions, however, a control relay C may be energized for aperiod long enough to cause repeated cycles to be effected. To preventsuch conditions cut-01f relays such as 6CP are provided.

When relay 6CH is picked-up by the closing of a contact such as 259 ofrelay 3-'1C, relay 6LC is caused to be energized as described. Frontcontact 281 of relay 6LC energizes relay 6GP which closes its stickcontact 282. The stick circuit for relay 6CP also includes front coutact259 of relay 3-1C, so relay 6CP remains picked up until relay 3-1C dropsaway. Back contact 258 of relayfiCP opens the automatic pick-up circuitfor relay 6CH, and the stick circuit for relay 6CH is open at backcontact 261 of relay 6LC. Thus, relay 6CH is effectively deg energized.The cut-off relay 6CP (and 8CP) picks up when code transmission beginsand remains picked-up until'the'control relay C which called for thecode transmission is dropped away.

As described in the above Hailes et al. patent, the code communicationsystem. selectively transmits indication codes from the field stationsand operates track indication relays TK, switch indication relays NWKand RWK, and signal indication relays GK. Such operations and relays areindicated in Fig. 6, and specific indication relays have been shown anddescribed in Figs. 3A-3F.

In View of the above Hailes et al. patent and other well-known signalingsystems, the present disclosure does not show actual switch and signalcontrol circuits located in the field stations. The primaryconsideration here is to show means for selectively operating suchwell-known control circuits in response to the storage and transfer oftrain descriptions.

Operation Assume that a train is detected approaching the passing sidingarea (Fig. 1) from the left, via theapproach track section lAT. Theoperator, or dispatcher, at the control ofiice is informed of theapproach of the train by indication means such as a track occupancyindication light (not shown) in the track diagram on the control panel(Fig. 2). The operator is aware of the number and type of the traineither from reference to a train sheet or from information received fromthe last control oflice passed by the train, or from the description ofthe train displayed by an indicator at the preceding siding location.

The operator then effects the storage of a description for the train inthe storage indicator 1AN by operating a train description button on thecontrol panel. The button operated will be one inscribed with the propertrain identification number, and will be located either in the rowheaded S or the row headed 1, depending upon the classification(superior or inferior) of the train.

When a button is depressed, contacts of the button close (Fig. 3A) toselectively energize the code relays CR1-CR6 and to energize thetransfer relay CTN. Relay CTN will remain' energized as long as a buttonis held depressed, and the selectively energized code relays CR willalso remain energized.

The closing of front contact 70 of relay CTN applies (BX) energy to thefront contacts 71-76 of the respective code relays CRl-CR6. Any of thesecontacts 7176 which are closed in their front positions will connect(BX) energy to contacts 1-6 in indicator IAN (Figs. 3A and 313) throughfront contacts such as 77 of relay IATN and wires such as 78. IndicatorIAN then operates, as described, until its front'contacts 1-6 are closedin the same combination as that assumed by front contacts 71-76 of thecode relays CR1-CR6, at which time the motor in indicator IAN is cut offand the latching relay LR releases to lock the indicator mechanism inplace. At this time the indicator tape displays the same number as thenumber of the operated train description button.

As soon as the indicator IAN completes its operation the operatorreleases the train description button, resulting in the deenergizationof relay CTN and the opening of the pick-up busses for relays CR1CR6.The selected code relays CRl-CR6 do not drop away, however, until theirstick circuits are opened by the opening of front contact 83 of relayCTN. Front contact 70 of relay CTN opens to remove (BX) energy from thecontacts 71-76 of relays CRl-CR6, thereby removing energy (BX) from theindicator lAN. As previously described, relay CTN functions to hold anycode relays CRl-CR6 energized through its front contact 83 so that theserelays are deenergized concurrently with the removal of (BX) energy fromthe control circuits for indicator IAN by the opening of front contact70 of relay CTN. In this manner, possible differences in release timesof the code relays CR1CR6 cannot cause further operations of indicatorIAN' which would result if the combination of closed front and backcontacts 71-76 were changed.

As previously described, train descriptions stored in an indicator canidentify a train as being superior or inferior. Superior descriptionsall call for indicator positions in which front contact 6 in theindicator is closed. In the present description of operations associatedwith a single train approaching from the left, superior and inferiorclassifications are immaterial, but will be carried through thedescription of operation.

When the train occupies track section IT, the associated track circuitis shunted causing the code communication system to perform anindication cycle during which indication codes are sent to the controloflice from field station -6. The characters of the indication codes aresuch that the track indication relay ITK is picked up. Since relay 1T Kis of the magnetic stick type, it will remain picked up until knockeddown in response to later indication codes which will be transmittedwhen track section IT is vacated. Such operations are fully described inthe above cited patent to Hailes et al.

When back contact 112 of relay ITK opens (Figs. 3A3B relay IATN isdeenergized. Front contacts such as 77 of relay IATN open the circuitsconnecting the code relays CRI-CR6 to the indicator IAN, and frontcontact 82 of relay IATN disconnects the motor of indicator IAN from(NX) energy. Front con-tact 112 of relay ITK closes, causing the pickingup of the transfer relay ITN. Front contacts such as 86- of relay ITN 87to apply (BX) energy to the front contact bus in indi-- cator IANthrough wire 88.

The applied (BX) energy reaches the latching relay LR and the motor inindicator 1N through the various closed front contacts 16 in indicatorIAN, back contacts such as 85 of relay IWS, front contacts such as 86 ofrelay ITN and various closed back contacts 16 in indicator 1N. Since thelatching relay LR and motor in indicator 1N are also connected to (NX)energy through back contact 95 of relay 1R0, the latch relay LR andmotor are operated until the indicator 1N assumes an operated positionidentical to that of the indicator IAN. At this time the train numbersdisplayed by the two indicators IAN and IN are identical, and thealignments of the contacts 16 in the respective indicators are the same.

During the described transfer operation, the latching relay and motor-inindicator IAN couldbe connected periodically to (BX) energy throughvarious feed-around paths including contacts 16 in indicator 1N and anyclosed back contacts 16 in indicator IAN. Therefore, indicator IAN couldbe erroneously operated during the read-out operation unless its motorcircuit is interrupted. For this reason front contact 82 of relay IATNis provided in the motor circuit to disconnect the motor and latchingrelay LR in indicator IAN from (NX) energy while (BX) energy is beingapplied for read-out transfers by back contact 87 of the same relayIATN.

When relay ITN is picked up to operate indicator IN to store the traindescription already stored in indicator IAN, front contact 216 of relayITN closes in the pickup circuits for the control relays 1-2C and 13C.The Picking up of one or the other of these relays will, as described,operate the code communication system (Fig. 6) to send selected controlcodes to field station 6 (Fig. 1), resulting in the positioning of trackswitch 7W and the clearing of signal 6R. As previously stated, it willbe assumed that any single train will be routed straight through thestretch of track via track section 2T unless the presence of othertrains make it necessary to route the train into the passing siding(track section 3T). Thus, control relay 1.2C which controls routes fromtrack section IT to track section 2T should be picked up under thepresent conditions. It can be seen in Figs. 3B and 30 that the closingoffront contact 216 of relay ITN completes a pick-up circuit for relay1-2C, while no 22 closed pick-up circuit for relay I-3C is available.Spe' cifically, the pick-up circuit for relay 1-2C includes back contact215 of relay IWS, front contact 216 of relay ITN, back contact 217 ofrelay 7DTK, wire 218, back contact 219 of relay 2TK, wire 220 and backcontact 221 of relay 4DC.

The picking up of relay 1-2C activates the code communication apparatus(Fig. 6), as previously described, and contacts-271, 273 and 277 ofrelay 1-2C select code characters to be transmitted calling for thenormal (straight through) position of track switch 7W and for theclearing of signal 6R. When such controls have been effected, indicationcodes are transmitted to the control officec'ausing the operation of thenormal switch indication relay NWK for switch 7W and the signalindication relay GK for signal 6R. Thus, in Figs. 3B-3D, front contactssuch as 91 of relay 7NWK are closed, indicating that switch 7W is in itsnormal position.

When the train accepts signal 6R and advances across track section 7DTand into track section 2T (Fig. 1) indication codes are transmitted tothe control ofiice for operating relays 7DTK and 2TK to indicate trackoccupancies.

At the time when the train was indicated entering track section 1T,causing the picking up of relay ITK, front contact of relay ITK closed(Figs. 3B-3C) the pick-up circuit for the directional relay 1-2D; thispick-up circuit also includes wire 161 and back contact 162 of relay2TK. When relay 2TK is picked up in response to the indicated occupancyof track section 2T,

the directional stick relay 2E8 is energized. The pickup circuit forrelay 2ES includes front contact 163 of relay 2TK and front contact 164of relay 1-2D; and a stick circuit for relay ZES'including its stickcontact 165 and front contact 163 of relay 2TK closed. Relay 2E8 remainsenergized until track section 2TK is indicated as being unoccupied.

At the'time when relays 7DTK and 2TK pick up, back contact 162 of relay2TK opens to deenergize relay 12D and back contact 217 ofrelay 7DTKopens the energizing circuit for relayI-2C; Relay 'I-ZD is slow-acting,

136 of relay 12C. Relay 1R0 is then held by a stick' circuitincludingstick contact 140 of relay IRO and front contact 141 of relayITK. The slow-acting re.- quirements for relay 1 2C are now evident inthat this relay must not open its front contact 136 until relay 1R0- canbe picked up,

Thepicking up of relay 1R0 results in the picking up of transfer relay2TN and in the application of readout energy (BX) to the indicator 1N.Front contact 116 of relay 1R0 closes a pick-up circuit for relay Relay2TN then closes its front contacts such as 90.

Read-out energy (BX) is applied to the contacts 16' in indicator IN byfront contact 94 of relay 1R0, while back contact 95 of relay 1R0 opensthe motor circuit for indicator 1N. Since at this time the circuitsinter= connecting the respective contacts 16 in indicators 1N and 2N areclosed through front contacts such as 9.0 i

and 91 of relays 2TN and 7NWK, respectively, (BX) energy is applied tothe motor and latching relay LR in indicator 2N; and the motorand-latching relay are also connected to (NX) energy through backcontact 97 of relay 2R0. The indicator 2N is thereby operated to thesame position as that assumed by indicator IN. Thus, the indicator 2N isoperated to display and store the description for the train when thetrain is detected entering track section 2T,

